This is how I was instructed by the person who inspected my garden for my nursery license. I treat all plants as if they were being shipped to California. No plants should be shipped across state lines without a nursery license!!
After digging, trim the tops and remove all dirt from the roots using a garden hose. Pull off a few off the outer leaves (where slugs and bugs may hide).
Immerse the roots (not the whole plant) in a 10% bleach solution which will remove any remaining dirt residue and kill any insects or larvae hidden in and around the roots. Rinse again with water.
Immerse the whole plant in water so that any hidden bugs/slugs will be killed or crawl out.
As an additional step, I stand the plants upright with just the roots in plain water for several hours to make sure they are hydrated for their long journey.
After drying, I do a final trim cutting excessively long roots, removing all the tiny hair roots (they will die anyway), and away they go in a box wrapped in newspaper. The roots are well hydrated, dry but not excessively dry.
